Few things in life are simply black or white, but for gourmets the world over, truffles are an exception. The black truffle (Tuber melanosporum) and the white truffle (Tuber magnatum pico) stand head and shoulders above all other truffles, both in flavour and in price.
Black truffles (around £2 per gram) are also known as Périgord truffles, after the region of southwest France where they have traditionally flourished. Like all truffles, they are the fruiting bodies of a mycelium, a kind of underground fungal “cobweb” that flourishes especially well next to oak trees. Enterprising farmers can buy young oaks – truffiers – that have been injected with truffle spores: after four to seven years or so they might well start producing a steady supply of “black diamonds” every winter, although success is far from guaranteed.
The spiritual home of the white truffle – its flesh is actually off-white and veined with brown – is about 450 miles east in Italy, in the hills around Alba, Piedmont. The Alba truffle (around £4 per gram) grows in a similar way to the Périgord truffle, but its season is earlier, typically from October to late December, and white truffles cannot be farmed. While black truffles can be cooked, the aroma of white truffles is easily destroyed by heat, so it is best treated as a condiment rather than an ingredient and simply grated onto food.
Both white and black truffles are foraged in the same way, by dogs of various breeds, usually trained from puppyhood to sniff out the precious fungus: one technique involves rubbing truffle oil on the mother’s nipples. Pigs, banned from foraging in Italy because of the damage they cause to the mycelium, are still used in parts of France: the sow can sniff out truffles up to a metre deep and their aroma contains the same hormone that male pigs secrete in their saliva.
Assuming you (and the dog or pig) have rootled out your truffle – black or white – what next? Firstly, use it as soon as you can: it has a shelf life of a week or so and its aroma will start to deteriorate immediately. Store it in kitchen paper or a jar of rice in the fridge to stop condensation softening it: rice will pick up some of the flavour and can be used for risotto. Eggs – wash and dry them first to increase the porosity of the shells – placed next to a truffle will absorb the flavour too, and are delicious scrambled with plenty of butter.
Truffles love fat, which has big molecules that act like a loud hailer for the truffle’s aroma. In Piedmont, egg yolks – which are around 25 per cent fat – are a favourite vehicle for white truffle; it is grated over fonduta – a rich, fondue-like mix of fontina cheese and egg yolks – or tajarin, the local version of tagliolini. Actually, ask anyone from Piedmont how you should eat truffle and they are very likely to reply, “Due uova fritte” (two fried eggs).
In France, because of the black truffle’s versatility, there are thousands of ways of using it, from the simple but extravagant method of wrapping it whole in tin foil with a nip of brandy and cooking it in the embers of a fire, to an elaborate poularde demi-deuil: this Lyonnais classic is a chicken cooked slowly in stock, with half the breast covered in slices of black truffle under the skin (demi-deuil means, literally, “half in mourning”).
Classic French cuisine often partners truffle with other luxury ingredients – tournedos Rossini, for instance: a piece of fillet steak topped with foie gras and black truffle, then served with a Madeira sauce. Claude Bosi, the two Michelin-starred chef/patron of Bibendum, recalls a meal at L’Ambroisie, the famous Paris restaurant. “I asked what was in the feuilleté de truffe fraîche ‘bel humeur’ and the waiter said, ‘Just truffle and foie gras.’ So I ordered it and that’s what it was: foie gras sandwiched between two thick slices of truffle, wrapped in puff pastry. It must have cost €200, but it had a magical earthiness. It was worth every cent.”
Playing on a similar theme, King’s stocks a truffled goose foie gras en croûte (from £176) produced by the distinguished Strasbourg foie gras-maker Georges Bruck.
Unsurprisingly, given the scarceness and expense of both black and white truffles, a huge market has emerged of truffle-flavoured products. Stick your nose into the annual truffle fair in the middle of Alba and you will be hit by a pungent wall of aroma: most of it will come not from the carefully wrapped “white diamonds” themselves, but from the myriad other products flavoured with synthetic truffle aroma: pasta, honey, oil, salt, rice, butter, even vinegar.
These products vary hugely in quality. The specks of truffle in honeys and oils may well be Tuber aestivum, the lesser-regarded summer truffle, while other products may simply contain too much of the truffle molecule. According to Paolo Montanaro, CEO of TartufLanghe, one of Piedmont’s leading truffle businesses, “A kilo of white truffles might contain, say, 10g of the truffle molecule, while a small bottle of oil might contain 50g.” Consumers demand a strong flavour. “That’s fine if it is in a condiment, like truffle salt – you can decide how much to use according to your personal taste – but when it’s in dried pasta, for example, it can be too strong and indigestible. The body doesn’t metabolise the truffle molecule, so too much of it can leave you with the smell for a day or so.”
Check the label of any product and make sure it lists either Tuber magnatum pico or Tuber melanosporum as an ingredient; once that has been established, use it sparingly – the idea is to enhance, not overwhelm. And proper truffle products are, by their nature, expensive: if the cost of something seems too good to be true, it almost certainly is.
Some of the best truffle products are oils and butters – the fat traps the aroma. Fortnum & Mason stocks Umbrian extra virgin olive oils infused with proper truffle (white, £45 for 55ml; black, £16.95 for 55ml); while Vallebona, an Italian delicatessen in Wimbledon, sells a fine, fragrant white truffle butter online (£18.99 for 50g – stir a teaspoonful or two into scrambled eggs or risotto). As to truffle salt, TartufLanghe has grey salt from Guérande flavoured with slices of white truffle (€9.60 for 30g); and don’t ignore truffles’ affinity with sweetness: truffled honey is an imaginative addition to a cheeseboard and works well with pecorino and slices of ripe pear (the online French grocer Gourmandise de Luxe has a Maison de la Truffe black truffle-infused acacia honey, €16 for 80g, which is perfect with sheep and goat’s cheese).
Montanaro’s company, meanwhile, has successfully pioneered another way of enjoying truffle out of season: freeze-dried, sliced white (€109 for 2.5g) and black truffle (€76 for 2.5g). The process removes the water from the truffles, which is what causes them to spoil, extending their shelf life for two years. “Just use them as you normally would on a warm dish of eggs or cheese,” advises Montanaro, “and the aroma will be released after a minute or two.”
He has an almost evangelical role in promoting and safeguarding Alba’s white truffle production. “Many truffle woods were lost when Nebbiolo, the grape that makes barolo and barbaresco, became popular 50 years ago and farmers started planting vineyards. And there is such demand that many of the truffles for sale in Alba are not from Alba.” There is, he says, a distinct difference between the Alba truffles and white truffles from elsewhere in Italy and eastern Europe. “They are sweeter, more delicate and don’t smell so strongly of garlic. It’s down to the soil, the altitude and the climate: what the French call terroir.”
His main crusade is traceability. “Truffle hunters often won’t tell you where they found their truffles – they won’t even tell their wives – so it can be difficult to reassure customers about their provenance. We now have 26 hectares of woods in which we can control everything – cutting branches to encourage more roots to grow, treating the soil with calcium carbonate in the spring – and we are working towards having truffles with a QR code, so consumers will know exactly where and when their truffle was found.”
In London, Jacob Kenedy, the chef/proprietor of Bocca di Lupo in Soho, gets his truffles from a variety of sources: “Sometimes dodgy little men who come by like drug dealers, but we have a couple of people we use regularly. And we sell them at Gelupo, our deli across the street: you can bring your truffle, wherever you’ve bought it, to the restaurant and we will shave it for free.
“My advice would be not to stint on truffle: you need five to 10 grams per dish to get the proper effect: better to splurge it on one dish than to spread it out.”
Kenedy is wary of truffle oil. “Chefs often add it to summer truffle to give more flavour, but I prefer just to use it in dressings. And I do know someone who loves to have his feet massaged with truffle oil, but,” he is quick to add, “that’s not a service we offer at Bocca di Lupo.”